Process op making briquettes containing phosphate rock



Patented J an. 10,

" UNITED STATES" PATENT OFFICE.

JAMES L'BABR, or n'ovmrrmaasim'r, TENNESSEE, ASSIGNOB To THE INTERNA- rxonar. AGRICULTURAL 'coarona'noiv, or NEW YORK, N. Y., a CORPORATION or NEW YORK.

rnocnss or inmate nnmum'rias con'ranimo PHOSPHATE 3001:.

I Drawing.

In the manufacture of phosphorus or phosphoric acid directly from phosphate rock by smelting in the electric or combustion furnace, the phosphate roclr material 6 is suitably ground and mixed with the required quantity of coke and silica to accomplish the reduction of the phosphorus to elemental form. In case phosphoric acid is sought directly, furnace conditions are regu:

10 lated so as to oxidize the phosphorus formed to phosphoric" acid anhydrid P 0 It has been proposed to briquette the phosphate rock, coke and silica; mixture before introduction into the furnace with or with out the use of an added bindingmaterlal of some sort. I have now discovered that a superior product may be had it the bIlquettes so formed are heated to approximate- 1y read heat or higher whereupon It will be found that the particles comprising the briquette will be bound into a firm,- coherent structure which is capable of bein exposed to the weather for an indefinite time without undergoing disintegration or having Its properties in an wa impaired. I

Preferably, re entirely .upon the natural plasticit of t e phosphate rock material, w ich is ue largely to the presence of clayey material, to act as a binder, thereby so eliminating the use of binding materials, such as pitch, sulphite liquor, etc., and furthermore producing a briquette which contains the maximum amount of the reacting materials.

In makin my improved briquette I may proceed as follows:

I suitablyl prepare the phosphate rock material whic may be the ordinary mine run hosphate. or the so-called pebble variety,

to y reducing it to a more or less uniform size, say to pass a one-sixteenth inch slot.

I then mix the ground phosphate rock with a finely divided carbonaceous material, such as coal or coke and silica in the correct pro- 5 portions for the phosphate reduction, using tc-r the purpose an ordinary paddle mixer. case the phosphate material runs high in Application filed April 9, 1824'. Serial No. 705,403.

silica, as is sometimes the case, no additional silica need be added. A typical composition would be as follows:

Parts. Phosphate rock (30% P 0 62 Pulverized coal 20 Silica including that silica contained in phosphate rock 18 Total The materials having been thoroughly mixed and a suitable amount of water added to g ve the roper consistency, the mixture is fed to a riquetting machine, such, for example, as a Belgium roll machine, and

formed into briquettes under a pressure of about 8000 pounds per square lIlCll. The green briquettes are then fed to a kiln of suitable type where they are subjected to a gradually increasing temperature until they ire finally subjected to a cherry red to red eat.

' Briquettes treated in this way will be found to have a structure strong and coherent enough tmwithstand all ordinary handling, and, in addition, they will be water-proof and may be stored without harm in the open for extended periods. If the final calcining temperature be high enough, theexterior surface of the bri uettes may have a glazed appearance. Usua ly, the Slll'c face is similar to that of common red brick, hard baked but not fused.

In the illustrative example above I have specified pulverized coal as the carbonaceous material used instead of the customary coke, the former material having the advantage that the volatile matter produced burns in the kiln and furnishes additional heat in the calcining. Equally satisfactory briquettes may however be produced using coke. While I have described my invention with particular reference to the production of a briquette containing carbon and silica, it will be understood that a water-proof briquette of phosphate rock material without these additions is within the purview of my amourits of clay V stantially water-liroof briquette which comprise mixing about six parts of ground hosphate rock, two parts of pulverized 00a and two parts 9f silica, forming the mixture into a briquette and heating the briquette to approximately red head;

JAMES A. BARR.

CERTHICATE 0F CORRECTION.

Patent No. 1,655,981. Granted January 10, 1928, to

JAMES A. BARR.

it is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, line 14, last word of claim, for the word "head" read "heat"; and that the said Letters Patent should he read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 13th day of March, A. D. 1928.

M. J. Moore, Seal. Acting Commissioner of Patenta. 

